Just to be clear, you should not have to move your data. I would suggest reformatting the µSD Card and then you could try reloading your data to it. But, since the Montana is working OK in this data configuration and you're on the road, maybe just leave well enough alone for now.

Hope you have a great ride.

Cheers,

It has been working perfectly ever since I moved my data to internal storage. It is mind-boggling to me how such an innocuous change can transform the Montana from a next-to-useless device to a well-functioning GPS. I'm going to leave well enough alone at this point, as you've noted.